Question: $ { \left[\begin{array}{rrr}{-1} & {0} & {0} \\ {-2} & {-1} & {4}\end{array}\right]+\left[\begin{array}{rrr}{2} & {3} & {-1} \\ {4} & {0} & {0}\end{array}\right] = {?} } $
Solution: To find the sum of two matrices, add the corresponding items between each matrix. ${\left[\begin{array}{rrr}{-1}+{2} & {0}+{3} & {0}+{-1} \\ {-2}+{4} & {-1}+{0} & {4}+{0}\end{array}\right]}$ Now, simplify: ${\left[\begin{array}{rrr}{1} & {3} & {-1} \\ {2} & {-1} & {4}\end{array}\right]}$